Table 7-1.—M50 Configuration Ammunition Characteristics
M54A1 HIGH-PRESSURE TEST
Both the M56A3 and M56A4 are loaded with
CARTRIDGE
aluminized composition A-4. The major difference
between the projectiles is their construction, The
The M544A1 cartridge is used only for proof firing
M56A3 has a baseplate to prevent ignition of the HEI
of the gun at the place of manufacture. The projectile is
charge by the propellant. The M56A4 does not have the
made from a solid steel bar. It has a standard rotating
baseplate, and it has approximately 10 more grains of
band. The M103 or M103B1 cartridge case is used with
A-4. Both cartridges use the M103 case, M52A3B1
the M52A3B1 electric primer.
electric primer, and the M505A3 PD fuze.
M55A2 TARGET PRACTICE CARTRIDGE
The M55A2 cartridge has no explosive filler in the
projectile. The solid nose is made of aluminum alloy.
The projectile shape and ballistic properties are similar
to those of the other M50-configured ammunition. The
cartridge is used for practice firing, boresighting
weapons, and testing new guns. The M103 cartridge
case and M52A3B1 electric primer make up this
cartridge.
M56A3 HIGH-EXPLOSIVE INCENDIARY
CARTRIDGE
The M56A3 or M56A4 projectile is used in the
M56A3 cartridge. The projectile is loaded with an
incendiary and explosive composition, giving the
combined effect of the blast of a high-explosive charge
plus a fire-starting ability.
M220 TARGET PRACTICE-TRACER
CARTRIDGE
The M221 projectile is used with the M220
cartridge. The M221 projectile is similar to the M55A2
projectile, except it incorporates a tracer in the base of
the projectile.
M242 HIGH-EXPLOSIVE
INCENDIARY-TRACER CARTRIDGE
The M242 projectile is used with the M242
cartridge. The projectile has a tracer in the base and
aluminized composition A-4 in the forward section. It
has a combined effect of a high-explosive charge plus a
fire-starting ability. The projectile is assembled with the
M505A3 PD fuze, the M103 case, and the M52A3B1
electric primer.
7-3
